/* Arithmetic problem with 1 operator */
#additionAndSubtractionOfCoins {
  font-size: 4em;
}
#additionAndSubtractionOfCoins span.operator, 
#additionAndSubtractionOfCoins span.equalitySymbol {
  margin-left: 0.4em;
  margin-right: 0.4em;
}
#additionAndSubtractionOfCoins input[type=number] {
  width: 1.5em;
}

